Companies are continually looking for new ways in which to increase sales of their goods or services. In outlets such as supermarkets, signs or banners are displayed prominently which advertise goods or special offers. Many shoppers have become accustomed to such advertisements and do not pay them much attention. Other less direct techniques such as wafting pleasant smells (e.g. fresh bread) near a food aisle have also been tried. There are claims that this can help increase food sales as it can make shoppers feel more hungry or put them in a pleasant mood.
There is also some evidence to show that “subliminal” advertising techniques can help improve sales. It is known to briefly display an image on a screen during a film or television programme. A viewer may not be consciously aware of the image, but he/she may still be affected by it, e.g. quickly flashing up an image of a cold drink can cause some members of an audience buy a drink. In some countries there are rules regarding the use of such techniques in video presentations but they may be freely used in other types of media.